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# Redis Key Slot Calculator
A high performance redis cluster key slot calculator for node redis clients e.g. [node_redis](https://github.com/NodeRedis/node_redis), [ioredis](https://github.com/luin/ioredis) and [redis-clustr](https://github.com/gosquared/redis-clustr/).
This also handles key tags such as `somekey{actualTag}`.
## Install
Install with [NPM](https://npmjs.org/):
```
npm install cluster-key-slot --save
```
## Usage
```js
const calculateSlot = require('cluster-key-slot');
const calculateMultipleSlots = require('cluster-key-slot').generateMulti;
// ...
// a single slot number
const slot = calculateSlot('test:key:{butOnlyThis}redis');
// Buffer is also supported
const anotherSlot = calculateSlot(Buffer.from([0x7b, 0x7d, 0x2a]));
// multiple keys - multi returns a single key slot number, returns -1 if any
// of the keys does not match the base slot number (base is defaulted to first keys slot)
// This is useful to quickly determine a singe slot for multi keys operations.
const slotForRedisMulti = calculateMultipleSlots([
'test:key:{butOnlyThis}redis',
'something:key45:{butOnlyThis}hello',
'example:key46:{butOnlyThis}foobar',
]);
```
## Benchmarks
`OLD` in these benchmarks refers to the `ioredis` crc calc and many of the other calculators that use `Buffer`.
```text
node -v ✔ 16.38G RAM 10:29:07
v10.15.3
NEW tags x 721,445 ops/sec ±0.44% (90 runs sampled)
OLD tags x 566,777 ops/sec ±0.97% (96 runs sampled)
NEW without tags x 2,054,845 ops/sec ±1.77% (92 runs sampled)
OLD without tags x 865,839 ops/sec ±0.43% (96 runs sampled)
NEW without tags singular x 6,354,097 ops/sec ±1.25% (94 runs sampled)
OLD without tags singular x 4,012,250 ops/sec ±0.96% (94 runs sampled)
NEW tags (Buffer) x 552,346 ops/sec ±1.35% (92 runs sampled)
```